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Trying to read 700k+ of data and the Error "GC Overhead Limit Exceeded" occurred

Alright so I need help in reviewing my codes because I'm kinda still new in programming (currently in my second year of Diploma in Computer Science). I got this error as in the title GC Overhead Limit Exceeded when I tried running my code below.
A brief explanation of this code, I'm trying to read data from a CSV File and then transfer it to a database. FYI, there are actually 10 tables/CSV files that I need to read, but on this I'll show this one table Tickets because the error only occurred when I tried to read that table/file. The other tables have hundreds of rows/data only while the table Tickets have 735,504 of rows/data. Furthermore, I've succeeded in reading 450,028 of data after 6 hours of running the code before the error occurred.
What can I do to fix this error? What can be modified to improve my code? I really appreciate it if you guys can help me :)
public class Demo2 {
public static void main(String[] args) {
String url = "jdbc:mysql://localhost:3306/database";
String username = "root";
String password = "password";
try {
//Connect to the database
Connection connection = DriverManager.getConnection(url, username, password);
//Test on one table only
String tableName = "Tickets";
System.out.println("Connecting to TABLE " +tableName +"...");
readCSVFile(tableName, connection);
System.out.println();
System.out.println("THE END");
connection.close();//close connection to the database
}
catch (SQLException e) {
System.out.println("ERROR at main(): SQLException!!");
e.printStackTrace();
}
}
static int countNewRow = 0;
static int countUpdatedRow = 0;
//Method to read the CSV File
static void readCSVFile(String tableName, Connection conn) {
//Read CSV File
try {
String path = tableName +".csv";
BufferedReader br = new BufferedReader(new FileReader(path));
br.readLine();//skip the first line
String inData;
//Read The Remaining Line
while((inData=br.readLine()) != null)
{
String[] rowData = inData.split(",");
ArrayList <String> rowDataList = new ArrayList<String>();
for (int i=0; i<rowData.length; i++)
rowDataList.add(rowData[i]);
//To combine String that starts and ends with "
for(int i=0; i<rowDataList.size(); i++) {
if (rowDataList.get(i).charAt(0) == '"') {
String string1 = rowDataList.get(i).substring(1, rowDataList.get(i).length());
String string2 = rowDataList.get(i+1).substring(0, rowDataList.get(i+1).length()-1);
String combined = string1 +"," +string2;
rowDataList.set(i, combined);
rowDataList.remove(i+1);
break;
}
}
//Remove the RM
for(int i=0; i<rowDataList.size(); i++) {
if (rowDataList.get(i).startsWith("RM")) {
String string = rowDataList.get(i).substring(2);
rowDataList.set(i, string);
}
}
//This is just to keep track of the data that has been read
System.out.println("[" +rowDataList.get(0) +"]");
//Transfer the data to the database
insertToDatabase(conn, tableName, rowDataList);
}
System.out.println("New Row Added : " +countNewRow);
System.out.println("Updated Row : " +countUpdatedRow);
System.out.println("== Process Completed ==");
br.close();
}
catch (FileNotFoundException e) {
System.out.println("ERROR at readCSVFile(): FileNotFoundException!!");
e.printStackTrace();
}
catch (IOException e) {
System.out.println("ERROR at readCSVFile(): IOException!!");
e.printStackTrace();
}
catch (SQLException e) {
System.out.println("ERROR at readCSVFile(): SQLException!!");
e.printStackTrace();
}
catch (ParseException e) {
System.out.println("ERROR at readCSVFile(): ParseException!!");
e.printStackTrace();
}
}
static void insertToDatabase(Connection connection, String tableName, ArrayList <String> rowDataList) throws SQLException, ParseException {
String tableIdName = tableName;
if (tableIdName.charAt(tableIdName.length()-1) == 's')
tableIdName = tableIdName.substring(0, tableIdName.length()-1);
//To read row
String rowID = rowDataList.get(0);
String selectSQL = "SELECT * FROM " +tableName +" "
+"WHERE " +tableIdName +"_ID = " +rowID;
Statement statement = connection.createStatement();
ResultSet result = statement.executeQuery(selectSQL);
boolean value = result.next();
//INSERT # UPDATE row
if (value == true) { //Update Row if the data is already existed
updateStatementt(tableName, connection, rowDataList);
countUpdatedRow++;
}
else { //Insert New Row
insertStatementt(tableName, connection, rowDataList);
countNewRow++;
}
}
//Method to insert data to the database
static void insertStatementt(String tableType, Connection conn, ArrayList <String> rowDataList) throws SQLException, ParseException {
//Generate Question Mark
String generateQuestionMark = null;
if(rowDataList.size() == 1)
generateQuestionMark = "?";
else
generateQuestionMark = "?, ";
for(int i=1; i<rowDataList.size(); i++) {
if(i!=rowDataList.size()-1)
generateQuestionMark += "?, ";
else
generateQuestionMark += "?";
}
//Insert sql
String sql = "INSERT INTO " +tableType +" VALUES (" +generateQuestionMark +")";
PreparedStatement insertStatement = conn.prepareStatement(sql);
//Insert data
//There are other 'if' and 'else if' statements here for other tables
else if (tableType.equals("Tickets")) {
int ticketID = Integer.parseInt(rowDataList.get(0));
int movieId = Integer.parseInt(rowDataList.get(1));
int theaterId = Integer.parseInt(rowDataList.get(2));
String[] date = rowDataList.get(3).split("/");
String dateString = date[2] +"-" +date[1] +"-" +date[0];
Date showDate = Date.valueOf(dateString);
int showTimeId = Integer.parseInt(rowDataList.get(4));
int cptId = Integer.parseInt(rowDataList.get(5));
int pcId = Integer.parseInt(rowDataList.get(6));
float amountPaid = Float.parseFloat(rowDataList.get(7));
int year = Integer.parseInt(rowDataList.get(8));
String month = rowDataList.get(9);
insertStatement.setInt(1, ticketID);
insertStatement.setInt(2, movieId);
insertStatement.setInt(3, theaterId);
insertStatement.setDate(4, showDate);
insertStatement.setInt(5, showTimeId);
insertStatement.setInt(6, cptId);
insertStatement.setInt(7, pcId);
insertStatement.setFloat(8, amountPaid);
insertStatement.setInt(9, year);
insertStatement.setString(10, month);
}
insertStatement.executeUpdate();
insertStatement.close();
}
//Method to update the data from the database
static void updateStatementt(String tableType, Connection conn, ArrayList <String> rowDataList) throws SQLException {
Statement statement = conn.createStatement();
String sql = "UPDATE " +tableType;
//There are other 'if' and 'else if' statements here for other tables
else if (tableType.equals("Tickets")) {
String[] date = rowDataList.get(3).split("/");
String dateString = date[2] +"-" +date[1] +"-" +date[0];
sql += " SET movie_id = " +rowDataList.get(1) +","
+ " theater_id = " +rowDataList.get(2) +","
+ " showdate = \"" +dateString +"\","
+ " showtime_id = " +rowDataList.get(4) +","
+ " costperticket_id = " +rowDataList.get(5) +","
+ " personcategory_id = " +rowDataList.get(6) +","
+ " amount_paid = " +rowDataList.get(7) +","
+ " year = " +rowDataList.get(8) +","
+ " month = \"" +rowDataList.get(9) +"\""
+ " WHERE ticket_id = " +rowDataList.get(0);
}
statement.executeUpdate(sql);
}
}

For short, read a single line and do whatever you want to do with it. You don't have enough memory for all 700k lines.

You should add statement.close() for the update Statement.

If you really want to read all this data into the Java heap, increase the heap size using, for example, the -Xmx command-line switch. Because of the way textual data is encoded in the JVM, you'll probably need much more heap that the total data size would suggest.
In addition, there might be some places in your code where you can take the strain off the JVM's memory management system. For example, concatenating strings using "+" can generate a lot of temporary data, which will increase the load on the garbage collector. Assembling strings using a StringBuilder might be a simple, less resource-hungry, alternative.

Reading & Breaking CSV File in Java:

I am editing this question to be more specific and I've learned some Jave to find the solution to my problem. I have a file in CSV format like this:
or in excel like this:
Now I am using Java program to read the second line of file and separate each Comma Separated Value and write it to console as well as on other output file and it was done easily. Now I'm trying to break the last value of:
S/1,M/1,L/1,XL/1 | 2XL/1,3XL/1,4XL/1,5XL/1 | MT/1,LT/1 (Original)
S/1,M/1,L/1,XL/1,2XL/1,3XL/1,4XL/1,5XL/1,MT/1,LT/1 (Modified using program to remove spaces and replacing the Pipes (|) with comma.
In each value, There is the size name before Forward Slash (/) and its quantity is after that. What I'm trying is using the Forward Slash (/) to separate the size with its quantity. And the problem is that the size may contain the forward slash as well (e.g. 12/BT or 2BT/2x). I've tried many algorithms like reversing the whole array or storing the slash count but not getting the success. The whole code to read file and break the comma separated values into separate columns of file is as following:
import java.io.*;
import javax.swing.*;
public class ReadFile3c{
public static void main(String args[]){
try{
//Getting File Name
String fileName = JOptionPane.showInputDialog("Enter File Name") + ".csv";
//Creating Stream with File
FileReader fr = new FileReader(fileName);
//Applying Buffer Filter
BufferedReader br = new BufferedReader(fr);
//Reading First line then Second Line
String s = br.readLine();
s = br.readLine();
s = s + ",";//adding comma at the end of the file
s = s.replaceAll("\\s",""); //Eliminating Spaces
s = s.replaceAll("\\|",","); //Replacing Pipes with comma
char charArray[] = s.toCharArray();
//Declaring Strings and variablse for value separating function
int n = 0; //Array Variable
int m = 0; //Array Variable
String[] inverted = new String[3]; //String to store inverted Commas Values
String[] comma = new String[10]; //String to store comma Values
String value = ""; //Storing character values
try{
//Loop to cycle each character of file
for(int j = 0; j<charArray.length;j++){
//Inverted comma value separator
if (charArray[j] == '"') {
j++;
//loop to gather values b/w invreted comma
while((charArray[j] != '"')){
value = value + charArray[j];
j++;
}
inverted[n] = value;
n++;
j++;
value = "";
}else{
j = j - 1;
//comma Value separator
if (charArray[j] == ','){
j++;
//loop to gether values b/w commas
while((charArray[j] !=',')){
value = value + charArray[j];
j++;
}
comma[m] = value;
m++;
value = "";
}
}
}
}catch(Exception ex){
System.out.println("in inner Exception Block" + ex);
}
//declaring variables to storing values
String name, patternCode, placeSizeQty,width,length,utill,pArea,pPerimeter,totalPcs,placePcs,tSizes;
name = inverted[0];
patternCode = inverted[1];
placeSizeQty = inverted[2];
width = comma[0];
length = comma[1];
utill = comma[2];
pArea = comma[3];
pPerimeter = comma[4];
totalPcs = comma[5];
placePcs = comma[6];
tSizes = comma[7];
//printing all values on Console
System.out.println("\nMarkerName: " + name);
System.out.println("Width :" + width);
System.out.println("Length :" + length);
System.out.println("Utill :" + utill);
System.out.println("Place Area :" + pArea);
System.out.println("Place Perimeter :" + pPerimeter);
System.out.println("PatternCode: " + patternCode);
System.out.println("PlaceSizeQty: " + placeSizeQty);
System.out.println("Total Pcs :" + totalPcs);
System.out.println("Place Pcs :" + placePcs);
System.out.println("Total Sizes :" + tSizes);
//Creating Output file
String fileOutput = JOptionPane.showInputDialog("Enter Output File Name") + ".txt";
//File Writer
try{
//Creating Stream with output file
FileWriter fw = new FileWriter(fileOutput);
//Applying Buffring Stream
PrintWriter pw = new PrintWriter(fw);
//Declaration
String outputLine = null;
//Writing Inverted inputs
for (int u = 0; u <=2 ;u++ ) {
outputLine = inverted[u];
pw.println(outputLine);
System.out.println("Writing: " + outputLine);
}//end of for
//writing comma inputs
for (int t = 0;t <=7 ; t++ ) {
outputLine = comma[t];
pw.println(outputLine);
System.out.println("Writing: " + outputLine);
}//end of for
pw.flush();
pw.close();
fw.close();
fr.close();
br.close();
}catch(Exception ex){
System.out.println("Output: " + ex);
}//End of output catch
}catch(IOException ex){
System.out.println(ex);
}//end of catch
}//end of catch
}//end of Class
And the code to Break the Size and quantity and store it in Double array (Not completed) is as Following:
import java.io.*;
import javax.swing.*;
public class ReadFileInvert{
public static void main(String args[]){
try{
String fileName = JOptionPane.showInputDialog("Enter File Name") + ".csv";
FileReader fr = new FileReader(fileName);
BufferedReader br = new BufferedReader(fr);
String s = br.readLine();
System.out.println(s);
s = s.replaceAll("\\s","");
s = s.replaceAll("\\|",",");
System.out.println(s);
char charArray[] = s.toCharArray();
char charArrayI[] = new char[charArray.length + 1];
int j = 0;
String value = "";
for(int i = charArray.length; i > 0; i--){
charArrayI[j] = charArray[i];
value = value + charArrayI[j];
j++;
}
System.out.println("1" + value);
}catch(Exception ex){
System.out.println(ex);
}
}
}
Now in simple I just want to Separate the sizes (Which may contains the Forward Slashes) with its quantity (After last slash of each value) and store it in double array Like charArray[sizeName][Qty]. Sorry if i didn't explained my problem well as I'm Learning the Coding. but I'll provide as much info as you want.

Have you considered looking at the CAD software export to see if there is a solution on the file creation side? Or is this file coming from a third party?

OK. So, after the hard work of whole day, I've found the following solution to my problem:
import java.io.*;
import javax.swing.*;
public class ReadFileInvert2{
public static void main(String args[]){
try{
String fileName = JOptionPane.showInputDialog("Enter File Name") + ".csv";
FileReader fr = new FileReader(fileName);
BufferedReader br = new BufferedReader(fr);
String s = br.readLine();
System.out.println(s);
s = s.replaceAll("\\s","");
s = s.replaceAll("\\|",",");
System.out.println(s);
char charArray[] = s.toCharArray();
int x = charArray.length - 1;
charArray[x] = ',';
int no = 1;
int size = 1;
int qty = 2;
String sizeS = "";
String qtyS = "";
//String resSet[][] = new String[4][2];
String resSize[] = new String[20];
String resQty[] = new String[20];
int slashNo = 0;
String value = "";
for (int j = 1; j < charArray.length; j++){
int n = j;
if (charArray[j] == ','){
j++;
}
while (charArray[j] != ','){
if (charArray[j] == '/') {
slashNo = j;
//j++;
}
value = value + charArray[j];
//System.out.println(value);
j++;
}
for (int k = n;k < slashNo; k++ ) {
sizeS = sizeS + charArray[k];
//System.out.println(sizeS);
}
for (int l = slashNo + 1; l < j; l++ ) {
qtyS = qtyS + charArray[l];
//System.out.println(qtyS);
}
resSize[no] = sizeS;
System.out.println(resSize[no]);
resQty[no] = qtyS;
System.out.println(resQty[no]);
System.out.println("Size is: " + resSize[no] + ", and Qty is: " + resQty[no]);
no++;
slashNo = 0;
sizeS = "";
qtyS = "";
}
String fileOutput = JOptionPane.showInputDialog("Enter Output File Name: ") + ".txt";
try{
FileWriter fw = new FileWriter(fileOutput);
PrintWriter pw = new PrintWriter(fw);
String outputSize = null;
String outputQty = null;
for (int t = 1; t < no; t++) {
outputSize = resSize[t];
outputQty = resQty[t];
pw.println(outputSize + " = " + outputQty);
System.out.println("Writing: "+ outputSize + " = " + outputQty);
}
pw.flush();
pw.close();
fw.close();
fr.close();
br.close();
}catch(Exception ex){
System.out.println("Output " + ex);
}
}catch(Exception ex){
System.out.println(ex);
}
}
}
Now its in Generic form but will improve it later. But still its working fine. Thanks for your Help stack overflow Community.

My array Printing NULL

In the method, i have all these initialize
Scanner input = new Scanner(System.in);
File file = new File("order.dat");
File viewOrder = new File("ViewOrder.dat");
String orderNo, itemNo, itemNameHolder, qtyHolder, priceHolder, status;
int hold, count = 0, countArray = 0;
double tempPriceHolder, totalPrice = 0;
String tempStatus = "";
String[] holdItemNo = null;
String[] holdName = null;
Integer[] holdQty = null;
Double[] holdTotal = null;
String[] holdStatus = null;
After, i try to read all my content in the file and store the content into holdX array
try {
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
String line = null;
while ((line = br.readLine()) != null) {
String tokens[] = line.split(";");
orderNo = tokens[0];
itemNo = tokens[1];
itemNameHolder = tokens[2];
qtyHolder = tokens[3];
priceHolder = tokens[4];
status = tokens[5];
if (orderNo.equalsIgnoreCase(userOrderNo)) {
tempPriceHolder = Double.parseDouble(priceHolder);
hold = Integer.parseInt(qtyHolder);
tempPriceHolder = tempPriceHolder * hold;
totalPrice += tempPriceHolder;
countArray++;
holdItemNo = new String[countArray];
holdName = new String[countArray];
holdQty = new Integer[countArray];
holdTotal = new Double[countArray];
holdStatus = new String[countArray];
if (status.matches("s")) {
tempStatus = "Success";
} else if (status.matches("p")) {
tempStatus = "Partially Full";
} else if (status.matches("o")) {
tempStatus = "Out of Stock";
}
holdItemNo[count] = itemNo;
holdName[count] = itemNameHolder;
holdQty[count] = hold;
holdTotal[count] = tempPriceHolder;
holdStatus[count] = tempStatus;
count++;
}
}
} catch (Exception e) {
System.out.println("Error");
}
Final, i write all my array into a new file.
System.out.printf("%s %15s %15s %10s %10s\n", "Item No", "Description", "Quantity", "Total", "Status");
for (int i = 0; i < holdItemNo.length; i++) {
System.out.printf("\n%-11s %-18s %-13s $%-8s %s \n", holdItemNo[i], holdName[i], holdQty[i], holdTotal[i], holdStatus[i]);
}
System.out.println("-----------------------------------------------------------------------");
System.out.printf("%46s %s\n", "$", totalPrice);
System.out.print("Print Order to file Y/N: ");
String choice = input.next();
if (choice.equalsIgnoreCase("y")) {
try {
PrintWriter bw = new PrintWriter(new FileWriter("ViewOrder.dat", true));
for (int i = 0; i < holdItemNo.length; i++) {
bw.write(userOrderNo + ";" + holdItemNo[i] + ";" + holdName[i] + ";" + holdQty[i] + ";" + holdTotal[i] + ";" + holdStatus[i] + "\n");
bw.flush();
}
bw.flush();
bw.close();
System.out.println("Sucessfull!");
} catch (Exception e) {
System.out.println("Error");
}
} else if (choice.equalsIgnoreCase("n")) {
System.out.println("");
}
but the problem is even my code is working but the output is not what i expected. It printed out the printed out the last content and also the sub price is working as well but the rest is only printed out NULL.
Example
Also, it gave me warning of Derefencing possible null pointer on the array.length
for (int i = 0; i < holdItemNo.length; i++) {
bw.write(userOrderNo + ";" + holdItemNo[i] + ";" + holdName[i] + ";" + holdQty[i] + ";" + holdTotal[i] + ";" + holdStatus[i] + "\n");
bw.flush();
}

Guessing:
holdItemNo = new String[countArray];
and the following lines: you are creating these new array objects within your reading loop (inside a condition).
So probably that condition never goes true; therefore your arrays stay all null. But even when the condition is met - you probably expect that to happen more then once. And guess what: you are creating completely new arrays then. While throwing away the previously created array. Each time the if condition turns true you will lose previously stored values!
So the answer is: create your arrays before entering the loop. This means that you either have to query "how many slots to create" upfront; or you have to create an array with say 100 empty slots; and within your loop you then have to check if you still have free slots.
Or you start using java.util.List resp. ArrayList - which allows for dynamic adding of elements.

how to link a main class to a jframe form in java using netbeans

Good day!
I have created a code using Netbeans and it executes the processes just fine.
Now, i want my input to given and output to be displayed through a user interface. I have then created a 2 Jframes, 1 to collect the user's input and the other to display the results after execution by the code.
But, i am unable to link the interface to the main class(called NgramBetaE) as i am not aware of how i can do so.
I highly welcome suggestions.
The main class in its entirety is;
package ngrambetae;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.*;
/**
*
* #author 201102144
*/
public class NgramBetaE {
static LinkedList<String> allWords = new LinkedList<String>();
static LinkedList<String> distinctWords = new LinkedList<String>();
static String[] hashmapWord = null;
static int wordCount;
public static HashMap<String,HashMap<String, Integer>> hashmap = new HashMap<>();
public static HashMap<String,HashMap<String, Integer>> bigramMap = new HashMap<>();
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
//prompt user input
Scanner input = new Scanner(System.in);
//read words from collected corpus; a number of .txt files
File directory = new File("Corpus");
File[] listOfFiles = directory.listFiles();//To read from all listed iles in the "directory"
int lineNumber = 0;
String line;
String files;
String delimiters = "[()?!:;,.\\s]+";
//reading from a list of text files
for (File file : listOfFiles) {
if (file.isFile()) {
files = file.getName();
try {
if (files.endsWith(".txt") || files.endsWith(".TXT")) { //ensures a file being read is a text file
BufferedReader br = new BufferedReader(new FileReader(file));
while ((line = br.readLine()) != null) {
line = line.toLowerCase();
hashmapWord = line.split(delimiters);
//CALCULATING UNIGRAMS
for(int s = 0; s < hashmapWord.length; s++){
String read = hashmapWord[s];
allWords.add(read);
//count the total number of words in all the text files combined
//TEST
wordCount = 0;
for (int i = 0; i < allWords.size(); i++){
wordCount ++;
}
}
//CALCULATING BIGRAM FREQUENCIES
for(int s = 0; s < hashmapWord.length -1; s++){
String read = hashmapWord[s];
final String read1 = hashmapWord[s + 1];
HashMap<String, Integer> counter = bigramMap.get(read);
if (null == counter) {
counter = new HashMap<String, Integer>();
bigramMap.put(read, counter);
}
Integer count = counter.get(read1);
counter.put(read1, count == null ? 1 : count + 1);
}
//CALCULATING TRIGRAM FREQUENCIES
for(int s = 0; s < hashmapWord.length - 2; s++){
String read = hashmapWord[s];
String read1 = hashmapWord[s + 1];
final String read2 = hashmapWord[s + 2];
String readTrigrams = read + " " + read1;
HashMap<String, Integer> counter = hashmap.get(readTrigrams);
if (null == counter) {
counter = new HashMap<String, Integer>();
hashmap.put(readTrigrams, counter);
}
Integer count = counter.get(read2);
counter.put(read2, count == null ? 1 : count + 1);
}
}
br.close();
}
} catch (NullPointerException | IOException e) {
e.printStackTrace();
System.out.println("Unable to read files: " + e);
}
}
}
//COMPUTING THE TOTAL NUMBER OF WORDS FROM ALL THE TEXT FILES COMBINED
System.out.println("THE TOTAL NUMBER OF WORDS IN COLLECTED CORPUS IS : \t" + wordCount + "\n");
for(int i = 0, size = allWords.size(); i < size; i++){
String distinctWord = allWords.get(i);
//adding a word into the 'distinctWords' list if it doesn't already occur
if(!distinctWords.contains(distinctWord)){
distinctWords.add(distinctWord);
}
}
//PRINTING THE DISTINCT WORDS
System.out.println("THE DISTINCT WORDS IN TOTAL ARE :\t " + distinctWords.size() + "\n");
System.out.println("PRINTING CONTENTS OF THE BIGRAMS HASHMAP... ");
System.out.println(bigramMap);
System.out.println("================================================================================================================================================================================================================================================================================================================\n");
System.out.println("PRINTING CONTENTS OF THE TRIGRAMS HASHMAP... ");
System.out.println(hashmap);
System.out.println("================================================================================================================================================================================================================================================================================================================\n");
//QUITTING APPLICATION
String userInput = null;
while(true) {
System.out.println("\n**********************************************************************************************************************************************************************************************************************************");
System.out.println("\n\n\t\tPLEASE ENTER A WORD OR PHRASE YOU WOULD LIKE A PREDICTION OF THE NEXT WORD FROM:");
System.out.println("\t\t\t\t(OR TYPE IN 'Q' OR 'q' TO QUIT)");
userInput = input.nextLine();
if (userInput.equalsIgnoreCase("Q")) break;
//FORMAT USER INPUT
String[] users = userInput.toLowerCase().split("[?!,.\\s]+");
if (users.length < 2) {
userInput = users[0];
//System.out.println("\nENTRY '" + userInput + "' IS TOO SHORT TO PREDICT NEXT WORD. PLEASE ENTER 2 OR MORE WORDS");
//CALCULATING BIGRAM PROBABILITY
int sum = 0;
try {
for(String s : bigramMap.get(userInput).keySet()) {
sum += bigramMap.get(userInput).get(s);
}
String stringHolder = null;
double numHolder = 0.0;
for(String s : bigramMap.get(userInput).keySet()) {
//System.out.println("TWO");
double x = Math.round(bigramMap.get(userInput).put(s, bigramMap.get(userInput).get(s))/ (double)sum *100 );
if(s != null){
if(numHolder < x ){
stringHolder = s;
numHolder = x;
}
}
}
System.out.println("\nNEXT WORD PREDICTED IS '" + stringHolder + "'");
System.out.println("ITS PROBABILITY OF OCCURRENCE IS " + numHolder + "%");
} catch (Exception NullPointerException) {
System.out.println("\nSORRY. MATCH NOT FOUND.");
}
} else {
userInput = users[users.length - 2] + " " + users[users.length - 1];
// System.out.println("FROM USER WE GET....");
// System.out.println(bigrams.get(userInput).keySet());
/* CALCULATING TRIGRAM PROBABILITY*/
int sum = 0;
try {
for(String s : hashmap.get(userInput).keySet()) {
sum += hashmap.get(userInput).get(s);
}
String stringHolder = null;
double numHolder = 0.0;
for(String s : hashmap.get(userInput).keySet()) {
//System.out.println("TWO");
double x = Math.round(hashmap.get(userInput).put(s, hashmap.get(userInput).get(s))/ (double)sum *100 );
if(s != null){
if(numHolder < x ){
stringHolder = s;
numHolder = x;
}
}
}
System.out.println("\nNEXT WORD PREDICTED IS '" + stringHolder + "'");
System.out.println("ITS PROBABILITY OF OCCURRENCE IS " + numHolder + "%");
} catch (Exception NullPointerException) {
System.out.println("\nSORRY. MATCH NOT FOUND.");
}
}
}
input.close();
}
}
My first Jframe which i would like to appear upon running the project has got a single textbox and a single button;
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String usersInput = jTextField1.getText();
Interface1 s = new Interface1();
s.setVisible(true);
dispose();
}
i would like for the user to enter data in the textbox and when they click on the button 'predict next word' then the output from the code execution is displayed on the second jframe which has got 3 labels and relative text areas.
NOTE; i couldn't paste the screenshots but if you run the NgramBetaE class you will get an idea of how the interfaces will be as i tried to explain them.
Thank you

Don't even try to link your GUI code to your NgramBetaE code as you've more work to do since the NgramBetaE is little more than one huge static main method that gets user input from the console with a Scanner and outputs to the console via printlns. Melding these two is like trying to put a square peg into a round hole.
Instead re-write the whole thing with an eye towards object-oriented coding, including creation of an OOP-compliant model class with instance fields and methods, and a single GUI that gets the input and displays it, that holds an instance of the model class and that calls instance methods on this instance.
Consider creating non-GUI classes and methods for --
Reading in data from your text files
Analyzing and hashing the data held in the text files including calculating word frequencies etc...
Returning needed data after analysis in whatever data form it may be needed.
A method for allowing input of a String/phrase for testing, with return its predicted probability
Then create GUI code for:
Getting selected text file from the user. A JFileChooser and supporting code works well here.
Button to start analysis
JTextField to allow entering of phrase
JTextArea or perhaps JTable to display results of analysis
Note that you should avoid having more than one JFrame in your GUI. For more on this, please have a look at The Use of Multiple JFrames, Good/Bad Practice?

Exception in thread "main" java.lang.NullPointerException when trying to update file

I'm in a beginner CS class and I'm trying to update info in a file. The info in the array does get replaced temporarily; however, I am unable to save the changes to the file. And, even after it's replaced, I get the "null" error.
Here is my code, I have omitted the lines and methods that are unrelated:
public static void readData(){
// Variables
int choice2, location;
// Read file
File dataFile = new File("C:/Users/shirley/Documents/cddata.txt");
FileReader in;
BufferedReader readFile;
// Arrays
String[] code = new String[100];
String[] type = new String[100];
String[] artist = new String[100];
String[] song = new String[100];
Double[] price = new Double[100];
Double[] vSales = new Double[100];
// Split Variables
String tempCode, tempType, tempArtist, tempSong, tempPrice, tempVsales;
// Split
String text;
int c = 0;
try{
in = new FileReader(dataFile);
readFile = new BufferedReader(in);
while ((text = readFile.readLine()) != null){
// Split line into temp variables
tempCode = text.substring(0,5);
tempType = text.substring(5,15);
tempArtist = text.substring(16,30);
tempSong = text.substring(30,46);
tempPrice = text.substring(46,52);
tempVsales = text.substring(52);
// Place text in correct arrays
code[c] = tempCode;
type[c] = tempType;
artist[c] = tempArtist;
song[c] = tempSong;
price[c] = Double.parseDouble(tempPrice);
vSales[c] = Double.parseDouble(tempVsales);
c += 1; // increase counter
}
// Output to user
Scanner kb = new Scanner(System.in);
System.out.print("\nSelect another number: ");
choice2 = kb.nextInt();
// Reads data
if (choice2 == 5){
reqStatsSort(code,type,artist,song,price,vSales,c);
location = reqStatistics(code,type,artist,song,price,vSales,c);
if (location == -1){
System.out.println("Sorry, code not found.");
}
else{
System.out.print("Enter new volume sales: ");
vSales[location] = kb.nextDouble();
}
displayBestSellerArray(type,artist,song,vSales,c);
readFile.close();
in.close();
changeVolume(code,type,artist,song,price,vSales,c); // Method to rewrite file
readData();
}
}catch(FileNotFoundException e){
System.out.println("File does not exist or could not be found.");
System.err.println("FileNotFoundException: " + e.getMessage());
}catch(IOException e){
System.out.println("Problem reading file.");
System.err.println("IOException: " + e.getMessage());
}
}
/////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////
////////////////////////////////////////////////////////
///////////////// REQ STATS SORT METHOD ////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
public static void reqStatsSort(String[] sortCode, String[] sortType, String[] sortArtist,
String[] sortSong, Double[] sortPrice, Double[] sortVSales, int c){
// Variables
String tempCode, tempArtist, tempType, tempSong;
double tempVsales, tempPrice;
for(int j = 0; j < (c - 1); j++){
for (int k = j + 1; k < c; k++){
if ((sortCode[k]).compareToIgnoreCase(sortCode[j]) < 0){
// Switch CODE
tempCode = sortCode[k];
sortCode[k] = sortCode[j];
sortCode[j] = tempCode;
// Switch TYPE
tempType = sortType[k];
sortType[k] = sortType[j];
sortType[j] = tempType;
// Switch ARTIST
tempArtist = sortArtist[k];
sortArtist[k] = sortArtist[j];
sortArtist[j] = tempArtist;
// Switch SONG
tempSong = sortSong[k];
sortSong[k] = sortSong[j];
sortSong[j] = tempSong;
// Switch VOLUME
tempVsales = sortVSales[k];
sortVSales[k] = sortVSales[j];
sortVSales[j] = tempVsales;
// Switch PRICE
tempPrice = sortPrice[k];
sortPrice[k] = sortPrice[j];
sortPrice[j] = tempPrice;
}
}
}
}
/////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////
////////////////////////////////////////////////////////
/////////////// REQUEST STATISTICS METHOD //////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
public static int reqStatistics(String[] statsCode, String[] statsType,
String[] statsArtist, String[] statsSong, Double[] statsPrice,
Double[] statsVSales, int c){
// Variables
String cdCode;
// Obtain input from user
Scanner kb = new Scanner(System.in);
System.out.print("Enter a CD code: ");
cdCode = kb.nextLine();
// Binary search
int position;
int lowerbound = 0;
int upperbound = c - 1;
// Find middle position
position = (lowerbound + upperbound) / 2;
while((statsCode[position].compareToIgnoreCase(cdCode) != 0) && (lowerbound <= upperbound)){
if((statsCode[position].compareToIgnoreCase(cdCode) > 0)){
upperbound = position - 1;
}
else {
lowerbound = position + 1;
}
position = (lowerbound + upperbound) / 2;
}
if (lowerbound <= upperbound){
return(position);
}
else {
return (-1);
}
}
/////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////
////////////////////////////////////////////////////////
/////////////// BEST SELLER ARRAY METHOD //////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
public static void displayBestSellerArray (String[] displaySortedType,
String[] displaySortedArtist, String[] displaySortedSong,
Double[] displaySortedVSales, int c){
// Output to user
System.out.println();
System.out.println("MUSIC ARTIST HIT SONG VOLUME");
System.out.println("TYPE SALES");
System.out.println("--------------------------------------------------------------------");
for (int i = 0; i < c; i++){
System.out.print(displaySortedType[i] + " " + displaySortedArtist[i] + " "
+ displaySortedSong[i] + " ");
System.out.format("%6.0f",displaySortedVSales[i]);
System.out.println();
}
}
/////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////
////////////////////////////////////////////////////////
////////////////// CHANGE VOLUME METHOD ////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
///////////////////////////////////////////////////////
public static void changeVolume(String[] writeCode, String[] writeType,
String[] writeArtist, String[] writeSong, Double[] writePrice,
Double[] writeVSales, int c){
File textFile = new File("C:/Users/shirley/Documents/cddata.txt");
FileWriter out;
BufferedWriter writeFile;
// Variables
String entireRecord, tempVSales;
int decLoc;
try{
out = new FileWriter(textFile);
writeFile = new BufferedWriter(out);
// Output to user
for (int i = 1; i <= c; i++){
// Convert volume sales to String
tempVSales = Double.toString(writeVSales[i]);
// Get rid of decimals
decLoc = (tempVSales.indexOf("."));
tempVSales = tempVSales.substring(0,decLoc);
// Create record line
entireRecord = writeCode[i] + " " + writeType[i] + " " + writeArtist[i]
+ " " + writeSong[i] + " " + writePrice[i] + " " + tempVSales;
// Write record to file
writeFile.write(entireRecord);
if (i != c){
writeFile.newLine();
}
}
writeFile.close();
out.close();
System.out.println("Data written to file.");
}
catch(IOException e){
System.out.println("Problem writing to file.");
System.out.println("IOException: " + e.getMessage());
}
}
The last method, changeVolume(), is what isn't working. The error I get is
Exception in thread "main" java.lang.NullPointerException
at culminating3.Culminating3.changeVolume(Culminating3.java:508)
at culminating3.Culminating3.readData(Culminating3.java:185)
at culminating3.Culminating3.readData(Culminating3.java:167)
at culminating3.Culminating3.main(Culminating3.java:47)
Java Result: 1
Line 508 is:
tempVSales = Double.toString(writeVSales[i]);
in the changeVolume method().
So my program asks the user for a CD code to change the volume of sales, and sorts the arrays to perform a binary search if the inputted code exists. If it does, my program replaces the old volume of sales (which it does), and saves it with the changeVolume() method (which it doesn't do and gives me the error).
Please keep in mind I'm a newbie. It looks fine to me but I can't figure out why it's not working. I apologize for any messes in the code. writeVSales[] shouldn't be null because I assigned input in the readData() method?

Problem is here:
// Convert volume sales to String
tempVSales = Double.toString(writeVSales[i]);
// Get rid of decimals
decLoc = (tempVSales.indexOf("."));
tempVSales = tempVSales.substring(0,decLoc);
I suggest you to take some sample values and work on this first.
You can use StringTokenizer to perform this.

When you input the information into the writeVSales array you start at 0 (good) and increment c everytime a new item is added, whether or not there is a new item to add or not (again this is fine).
int c = 0;
try{
in = new FileReader(dataFile);
readFile = new BufferedReader(in);
while ((text = readFile.readLine()) != null){
// Split line into temp variables
tempCode = text.substring(0,5);
tempType = text.substring(5,15);
tempArtist = text.substring(16,30);
tempSong = text.substring(30,46);
tempPrice = text.substring(46,52);
tempVsales = text.substring(52);
// Place text in correct arrays
code[c] = tempCode;
type[c] = tempType;
artist[c] = tempArtist;
song[c] = tempSong;
price[c] = Double.parseDouble(tempPrice);
vSales[c] = Double.parseDouble(tempVsales);
c += 1; // increase counter
}
Later in changeVolume() your for loop starts at 1 and goes to c. So you are missing the first element and trying to add an element from an index that is null, hence the `NullPointerexception.
// Output to user
for (int i = 1; i <= c; i++){
//code
}
Change the for loop to start and 0 and go to i < c (i.e. c - 1):
for (int i = 0; i < c; i++){
// Convert volume sales to String
tempVSales = Double.toString(writeVSales[i]);
// Get rid of decimals
decLoc = (tempVSales.indexOf("."));
tempVSales = tempVSales.substring(0,decLoc);
// Create record line
entireRecord = writeCode[i] + " " + writeType[i] + " " + writeArtist[i]
+ " " + writeSong[i] + " " + writePrice[i] + " " + tempVSales;
// Write record to file
writeFile.write(entireRecord);
if (i != c){
writeFile.newLine();
}
}